Current schistosomiasis control strategies are largely based on chemotherapeutic agents and a limited number of drugs are available today. Praziquantel
(PZQ) is the only drug currently used in schistosomiasis control programs. Unfortunately, this drug shows poor efficacy in patients during the earliest infection phases. The effects of
PZQ appear to operate on the voltage-operated Ca
2+ channels, which are located on the external
Schistosoma mansoni
membrane. Because some Ca
2+ channels have dihydropyridine drug class (a class that includes nifedipine) sensitivity, an
in vitro analysis using a calcium channel antagonist (clinically used for cardiovascular hypertension) was performed to determine the antischistosomal effects of nifedipine on schistosomula and adult worm cultures. Nifedipine demonstrated antischistosomal activity against schistosomula and significantly reduced viability at all of the concentrations used alone or in combination with
PZQ. In contrast,
PZQ did not show significant efficacy when used alone. Adult worms were also affected by nifedipine after a 24 h incubation and exhibited impaired motility, several lesions on the tegument and intense contractility. These data support the idea of Ca
2+ channels subunits as drug targets and favour alternative therapeutic schemes when drug resistance has been reported. In this paper, strong arguments encouraging drug research are presented, with a focus on exploring schistosomal Ca
2+ channels.
